By Sharon Omahen
University of Georgia
Outside of the holidays, sweet potatoes tend to be a forgotten
vegetable, mentally packed away with the decorations. Bob Jarret,
though, thinks about them all the time. He can call most of the
700-plus varieties by name.
Jarret is a sweet potato curator at the U.S. Department of
Agriculture Plant Genetic Resources Conservation Unit in Griffin,
Ga. Basically, his job is to make sure none of these sweet
potatoes becomes extinct.
Providing germplasm for breeding
“The primary reason we maintain all these lines is to provide
plant material for scientists,” Jarret said. “Researchers are
always in need of certain traits to make a new variety better
than the existing one. One variety may not taste very (good), but
it’s valuable because it’s resistant to pests or drought.”
The sweet potato weevil, for instance, shut down production in
Georgia in the early 1990s. “If a variety was bred to be
resistant to this weevil, farmers could avoid this problem in the
future,” he said.
Most of the requests Jarret gets are from scientists. About 10
percent, though, come from home gardeners.
“Most people are searching for the kind they ate as a child or
the kind their grandfather grew,” he said. “Many grew up on a
farm and know the name of the variety.”
The older varieties are usually just as nutritious as the
newer ones, he said, but aren’t as attractive.
“The flesh isn’t as brilliant orange,” he said. “There have
been a lot of improvements made over the years in physical
appearance and yield.”
Jarret says the most popular varieties on the market today are
Beauregard and Jewel. “I can usually tell by looking whether or
not it’s a Beauregard,” he said. “The flesh is a very bright
orange.”
This description fits the bill for the atypical sweet potato,
but not the entire USDA collection.
“Some of the varieties in our collection have sweet roots and
some have roots that aren’t too sweet,” he said.
Not just for eating anymore
Jarret says people like sweet potatoes now for more than their
nutrition.
“More and more people are looking at sweet potatoes as
ornamental plants,” he said. “They want something unique that
their neighbors won’t have.”
Some sweet potato varieties have uniquely colored or
variegated leaves. The USDA collection in Griffin, though,
doesn’t include ornamental varieties.
“I’ve seen a lot of these popping up in local nurseries,”
Jarret said. “They make attractive pot plants, but I wouldn’t try
to eat the roots.”
Stored as little plantlets
To protect the hundreds of edible sweet potato varieties,
Jarret grows plants and removes small cuttings called plantlets.
These are stored in coolers and replenished every six months.
He also stores breeding material for peppers, watermelons,
squash, okra, eggplant and a few other plants like bottle gourds
and luffas.
“I maintain them today to assure they’re around tomorrow,”
Jarret said.
For more information on the USDA National Plant
Germplasm System,
see their Web site at www.ars-grin.gov/npgs/.
